sort by last then by first

[Andrew Dalke]

Padraig at Linux.ie replied to my post:
 > I was suggesting this as a way to auto convert data that
 > was already in string format. For e.g. if importing tabular
 > data, using split, then you get all string fields. Actually
 > it would be good if you could pass to split what format the
 > fields are, something like:
 >
 > line.split('\t',4,(str,int,float,str))

 >>> line = "Spam\t-1\t9.8\tEggs"
 >>> [f(s) for f, s in zip( (str, int, float, str), line.split('\t') )]
['Spam', -1, 9.8000000000000007, 'Eggs']
 >>>

 > > Why not just write this as Python code?
 >
 > speed

which is why I suggested
] f = attr("name1").reverse() + attr("name2").as(int) + \
]        col(4).as(float).reverse()
    ....
] and for optimization you can also implement
]
] f.sort(x)
]
] which would do the fast decorate, sort, undecorate.

This should be exactly as fast as anything you can do by
special encoding of the sort parameters in the sort() call.
Maybe even faster, because they way you want it implies
there may still be O(n Log(n)) function callbacks into
Python, which is not necessarily the case with
decorate/sort/undecorate.

And potentially nicer because I can extend the system as
I wish, in Python.

So again, the answer to your question/statement:
 > wouldn't it be cool if [].sort() took an optional parameter that
 > was essentially the --key option in gnu sort. in this e.g:

is no.

					Andrew
					dalke at dalkescientific.com